diff --git a/custom_components/petkit/sensor.py b/custom_components/petkit/sensor.py
index 17b014a..6f9818a 100644
--- a/custom_components/petkit/sensor.py
+++ b/custom_components/petkit/sensor.py
@@ -449,7 +449,11 @@ class PetKitSensorDesc(PetKitDescSensorBase, SensorEntityDescription):
             translation_key="drink_times",
             entity_category=EntityCategory.DIAGNOSTIC,
             state_class=SensorStateClass.MEASUREMENT,
-            value=lambda device: (len(device.device_records)),
+            value=lambda device: (
+                len(device.device_records)
+                if isinstance(device.device_records, list)
+                else None
+            ),
         ),
     ],
     Pet: [